The cheapest cars to run and to insure

To save you time and energy trying to work this out, car experts have already done this research. You can compare running costs of different models, including the ones you're looking to buy, on several sites, But, follow these rules to home in on the cheapest cars:

Smaller engines can be cheaper. The choice of a 1.0-litre or a 2.0-litre engine isn’t just about pure horsepower. A large engine will usually burn more fuel than a smaller one. So engine size is a vital consideration if fuel economy is an important factor in your decision.Of course, this depends on how you use the car. A small engine is most efficient when it’s used as intended, such as to pootle around town. If a small engine is used a high speed, it'll need to work much harder to keep the car moving - burning more fuel.

Petrol cars tend to be cheaper than diesel. Diesel engines are often more economical than their petrol counterparts. But don’t be fooled into thinking this definitely makes diesel a better option. These cars are more expensive, and they usually cost more at the pump than petrol.

Manual cars are cheaper than automatic. Switching between gears is extra work - particularly to those of us prone to stalling at traffic lights. Yet while automatics take some of the hassle out of driving, they come with a higher price tag.A manual Audi A3 diesel hatchback, for example, costs £20,801. This compares to the automatic version, at £22,290 – or a rise of £1,489. Yet many automatics are more fuel-efficient than their manual counterparts, as they 'know' the best gear to be in, so you could recoup the extra cost over time.

Hybrid cars are cheap to run, but cost more to buy. Technology is improving everyday with modern hybrids coming in all shapes and sizes, from superminis to luxury SUVs. Fuel-economy and cheap or even zero tax rates make part-electric models appealing, like the Toyota Prius. They also tend to hold their value for resale.But they usually cost more to buy – so weigh up the savings.

Check CO2 emissions, as it affects the duty you pay. Buyers of the most polluting cars pay the most road tax. But choose a car (such as the emission-free hybrid Toyota Prius) that produces less than 100g of CO2/km and you'll pay nothing at all.An average family-type car, like a Volkswagen Golf, will set you back £30 a year. See a full list of Vehicle Excise Duty rates plus how to calculate yours.

Smaller cars are cheaper to insure. If you’re looking to save money, you’ll want a car that’s cheap to cover. The cheapest to insure tend to have a lot in common, including size. Put simply, it’ll cost you more to insure a 4x4 than a small city runaround.Cars are placed in groups ranked between one and 50, using research by the Motor Insurance Repair Research Centre (Thatchem). This is based of a range of info including performance, safety features, price of a new model and cost of spare parts. The Hyundai i10, for example, is one of a handful of cars in group one, and thus is cheap to insure.Check the insurance group rating of the exact model you have in mind before buying at Thatcham Research. The higher the number, the bigger your premium is likely to be. It's also worth checking our Cheap Car Insurance guide to see what the likely cost is.

All the above's important, but if you want to nail the absolute cheapest cars to run, here they are (though do note these are all smaller cars):

Top 10 cheapest cars to run in the UK

[th]CAR[/th][th]ESTIMATED RUNNING COSTS PER MONTH OVER THREE YEARS (12,000 MILES/YEAR INCL DEPRECIATION, SERVICE AND MAINTENANCE)[/th]